This invention relates to open-end textile spinning machines of the type having, at each spinning station thereof, a receptacle or "trash box" which receives particles of leaf, seed, dirt, fly or other trash removed by a beater roll or the like from the textile fibers being processed. The invention more particularly relates to an improved system for the collection and removal from such trash boxes of the trash deposited therein.
It has heretofore been proposed to remove trash from the trash boxes of open-end spinning machines by pneumatic suction: see, e.g., U.S. Pat. Nos. 3,839,764, 3,834,145, 3,828,539, 3,800,521, 3,797,218, 3,792,575, 3,777,466, 3,777,329 and 3,763,641. In some of the prior systems there is continuously applied, to the outlet of each trash box of the spinning machines, suction of a magnitude sufficient to continuously evacuate from the boxes the trash deposited therein. Such systems require a suction-source of considerable size, and therefore are relatively expensive from the viewpoint of both acquisition cost and operating cost. Additionally, the continuous application to the trash boxes of suction of the aforesaid magnitude may cause an excessive quantity of valuable "spinnable" fibers to be sucked into the boxes from the beater rolls adjacent thereto. In other of the prior trash removal systems, suction is applied only intermittently to the trash box outlets. The duration of the time intervals between suction-applications is quite important in systems of this type. If the intervals are of too brief a duration, one encounters problems of the above-discussed type present in connection with continuous-suction systems. On the other hand, if the time intervals between the intermittent applications of suction are of too long a duration, another problem may arise. During those intervals when suction is not being applied to the outlets of the trash boxes, the trash therein is blown about by air currents produced within the boxes by the adjacent beater rolls or other sources. Such extraneous air currents may cause trash to escape from the boxes, either by undergoing reverse-passage through the box inlets or by passing through one of the additional openings frequently provided in the trash boxes for other purposes, prior to its being withdrawn through the box outlets by the next application of suction to such outlets. Most if not all of the trash thus escaping from the trash boxes will be re-introduced into the textile fibers being processed, thereby resulting in degradation of the quality of the yarn spun therefrom. Attempted solution of the aforesaid problem by adjustment of the time intervals between successive applications of the intermittent suction is difficult since the selection of intervals of a suitable duration is dependent upon, among other things, the variable quality of the silver being processed. More frequent applications of suction will be required if the sliver is of a low-grade, "trashy" quality than if the sliver is of a better quality. A timing of the intermittent suction in a manner satisfactory for sliver of one quality therefore will not necessarily be suitable when sliver of another, different quality is processed by the same spinning machine.